Grid coupled cell circuit



April 24, 1928. 1,667,383

C. F. JENKINS GRID COUPLED CELL CIRCUIT Filed Oct. 22. 1924 gwuentocPatented Apr. 24, 1928.

CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA.

GRID COUPLED CELL CIRCUIT.

Application tiled October 22, 1924. Serial No. 745,209.

This invention relates to radio circuits in which a light-sensitive cellis employed to modulate the circuit, and its principal object is to socontrol the circuit as to interrupt a continuous wave as though it werekey modulated;

With this, and other objects in View, the arrangement of the elements ofthe circuit is described herein, 'llustrated in the drawing, andparticularly pointed out in the claims.

The whole is a system for controlling an oscillator of radio frequencyby the action of light on alight-sensitive cell. It employs anoscillator circuit and a cell circuit, the two coupled through avariable (grid leak) resistance. In the drawing A is a light-sensitivecell; B a battery a variable resistance, through which the cell circuitis coupled to the grid circuit of the tube 1). i

With the cell A in the dark, the coupling resistance is adjusted untilthe tube circuit is oscillating. the balance of circuit A, B, C is upset(because the resistance of the cell falls when light 'falls thereon) andthe oscillation of the tube circuit ceases.

No means is shown for cutting the light oil the cell (ones hand wouldanswer), as this is no art of the invention, or required for an unerstanding of its operation.

What I claim, is- Y 1. The method of signalling by means of a highgfrequency oscillation generatorcontrolled'by a light sensitive cell,including the step of setting up "oscillations under dark conditions ofthe cell and suppressing osizlillations by projecting light upon sai fieU I I in the cell circuit; C,

When the light falls on the cell 2. In the method of transmittingsignals or the like involving the use of radio frequency oscillations,the step which includes interrupting the oscillations in accordance withlight transmission from a. given source.

3. In the method of transmitting signals or thelike including the use ofa thermionic oscillation generator having a light infiuenced balancedcurrent path normally operative in the absence of'light to permitoscillations, the step which includes interrupting oscillations byenergizing one of the current paths by a light responsive currentgenerai. The combination, in' an oscillation generator, includingcoupled input. and output circuits, of an auxiliary circuit containing alight sensitive cell conductively coupled thereby to the input circuit,a source of potential in the auxiliary circuit, and a resistance bridgedacross the input and auxiliary circuit, said resistance being adjustedto a value to permit the generator to oscillate when the cell is darkand to arrest oscillations when the cell is influenced by light.

5. The combination with an electron valve, of an oscillation circuitincluding the grid and filament electrodes of said valve, a cellcircuit, a light sensitive cell in said cell cir-. cuit, a battery insaid circuit, and a resistance bridged across said circuits and normallyadjusted to a value-to permit the oscillation circuit to oscillate whenthe resistance of the cell is at maximum. 7 v

In testimony whereof I have atfixed my signature.

CHARLES FRANCIS JENKINS.

